The present disclosure relates generally to medical devices and methods and, more particularly, to an automated system and method for detecting events related to ventilatory instability, such as sleep apnea.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Sleep apnea is generally described as a sleep disorder that is characterized by episodes of paused breathing during sleep. These episodes of paused breathing may occur repeatedly throughout sleep, and each episode may last long enough to cause one or more breaths to be missed. Such episodes may be referred to as apneas. A typical definition of an apnea may include an interval between breaths of at least 10 seconds, with a neurological arousal and/or a blood oxygen desaturation of 3% or greater. The actual duration and severity of each apnea may substantially vary between multiple patients. Further, duration and severity of apneas may vary throughout a period of sleep for a single patient. Indeed, sleep apnea may have a wide range of severity. For example, sleep apnea may include mild snoring, which may be related to incomplete and inconsequential airway obstruction, or severe apneas, which may result in hypoxemia. Sleep apnea commonly results in excessive daytime sleepiness. Further, sleep apnea can hinder cognitive function during the day due to sporadic sleep during the night resulting from recurrent arousals associated with the sleep apnea.
Although sleep apnea commonly affects obese patients, it may occur in patients with any body type. Indeed, sleep apnea is fairly common and causes undesirable symptoms of excessive daytime sleepiness, morning headache, and decreasing ability to concentrate during the day. Thus, it is desirable to diagnose and treat sleep apnea. Traditionally, sleep apnea is diagnosed utilizing an overnight sleep test referred to as a polysomnogram. This is generally performed in a sleep lab and involves the continuous and simultaneous measurement and recording of an encephalogram, electromyogram, extraoculogram, chest wall plethysmogram, electrocardiogram, measurements of nasal and oral airflow, and pulse oximetry. All or some of these and other channels may be measured simultaneously throughout the night, and complex recordings of such measurement may then analyzed by a highly trained clinician to determine the presence or absence of sleep apnea.